Electrical relays



United States Patent ELECTRICAL RELAYS Harry E. Ashworth, Penn Township, Allegheny County, Pa., assignor to Westinghouse Air Brake Company, Wilmerding, Pa., a corporation of Pennsylvania Application June 10, 1954, Serial No. 435,853 11 Claims. (Cl. 317-172) My invention relates to electrical relays, and particularly to biased neutral relays used in railway signaling systems.

In biased neutral relays, the armature of the relay is gravity biased and picked up only when the operating flu'x due to the energization of the operating windings of the relay is of a particular polarity. A source of polarizing flux, usually a permanent magnet, is provided for this type of a relay to hold down the armature of the relay. The magnetic arrangement of the relay is such that, when the relay is energized by a current of reverse polarity, the reverse operating flux of the windings and the polarizing flux have an additive effect in holding the armature down. It has been found that relays of this type when mounted in exposed areas may be operated upon reverse energization of the operating windings due to dirt or other foreign particles lodging between the armature and the hold-down pole pieces with which such relays are provided. In such instances the armature is held in spaced relation with respect to the hold-down pole pieces by the lodged particle so that the polarizing flux is ineffective in holding the armature in its biased position. The armature, if free to move, may thus be picked up upon reverse energization of the operating windings of the relay. The possible operation of prior art relays upon reverse energization of the operating windings also led to certain difiiculties in installing and testing the relays. Such relays, if inadvertently turned over in handling, held their armatures picked up after the relays were righted. Improper circuits would thus be completed over the closed front contacts of such relays.

it is therefore an object of my present invention to provide a relay of-the direct current polarized type which will pick up its armature only when the operating flux due to the energization of the operating windings isof a given polarity.

A further object of my invention is to provide, in a relay of the character indicated, auxiliary sources of polarizing flux to insure the proper operation of the relay regardless of the position in or to which the armature may be moved.

Another object of the invention is to provide, in a relay of the character indicated, a magnetic structure which will protect the auxiliary sources of polarizing flux from demagnetization should the operating coils of the relay be subjected to heavy current surges.

In carrying out my invention, a biased neutral relay, having main pole pieces on the depending ends of the two operating winding cores and hold-down pole pieces spaced from the main pole pieces between which two sets of pole pieces the armature may move, is provided in addition to the permanent magnets associated with the pole pieces, with auxiliary permanent magnets magnetically connected with the operating winding cores by magnetizable extensions. The auxiliary permanent magnets are parallel with the relay cores and so disposed that the polarizing flux through each of the cores of the relay is of opposite polarity. As will hereinafter be more fully delodged between I are soft iron shunts 14 and 15, and

2 scribed, the armature'is held down against the hold-down pole pieces by the polarizing flux due to the permanent magnets associated with the two sets of pole pieces of the relay. The magnetic structure is such that operating flux due to energization of the operating windings will, if of one polarity, aid the polarizing flux of the hold-down magnets to hold down the armature, whereas operating flux of opposite polarity will pick up the armature.

With the addition of the auxiliary permanent magnets magnetically secured to the relay cores, the polarizing flux due to these magnets will thread the magnetic extension pieces and the cores when the operating windings are deenergized, so that none of the polarizing flux crating and polarizing fluxes aid in picking up the armapolarizing flux of the auxiliary magnets will be of opposite polarity, so that very little or no flux is available at the main pole pieces to pick up the armature. Thus, in the event a foreign particle is the armature and the hold-down pole pieces, a reverse energization of the operating windings many times the usual magnitude will not pick up the armature.

Other objects and characteristic features of my invention will become apparent as the description proceeds.

I shall describe one form of an electrical relay embodying my invention, and shall then point out the novel features thereof in claims.

In the accompanying drawings wherein similar reference characters designate similar parts throughout the two views,

Fig. l is an isometric schematic view of the magnetic structure of my novel relay, while Fig. 2 is a front elevational view of the relay structure.

Referring now in detail to the drawings, the reference character 1 designates a relay embodying my invention. The relay 1 comprises two parallel magnetizable cores 2 and 3 supported on a suitable base or frame 4 of insulating material. The base 4 is formed with suitable openings 5 through which the lower ends of the cores extend. The lower ends of the cores 2 and'3 terminate in pole pieces 6 and 7,"'resp'ectively, which will hereinafter be referred to as the main pole pieces. The main pole pieces 6 and 7 are provided with pole faces 8 ,and 9,

. respectively. Secured to each of'the cores 2 and 3 in a suitable manne'r'is a pair of parallel, rearwardly extending magnetizable extensions 10a, 10b and 11a, 1112, respectively; each of the extensions being spaced apart on their respective cores. Wound about each of the cores 2 and 3 between the magnetizable extensions are operating coils or windings 12 and 13, respectively, the coils being series connected.

Secured to therearwardly extending ends of each pair of the magnetizable extensions 10a, 10b and 11a, 11!; permanent magnets 16 and 17, respectively. The permanent magnets are formed with slightly protruding pole faces which abut their respective shunts 14 and 15 and which are in line with their respective magnetizable extensions. The poles of each of the magnets have been arbitrarily designated north and south poles'as indicated by the legends N and S appearing in the drawings. The upper magnetizable extensions 10b and 11b havesecured thereto, as by magnetizable screws 18, abackstrap 19 of mag- 'a vzsasso netizable material, the backstrap bridging the two extensions at their front ends and the cores 2 and' 3.

The pole pieces 6 and 7 of the cores 2 and 3 have secured thereto as.- at their outer edges, two L-shaped pole pieces 20 and 21 and small, hold-down permanent magnets 22. and 23,. respectiveiy. Thesmall permanent magnets 22 and 23 are magnetized across their width,- the poles of the. magnets beingarbitrari-ly designated by the letters 'N" and S inthe. drawings. The L-shaped pole. piecesv and the permanent magnets are secured by magnetizable screws 24 so that the. hold-down magnets are interposed between pole. pieces 6 and7 and the. vertical or. upright arms 20a: and 21a of. the. pole pieces 2.0- and respectively; the horizontal arms. 20bv and: 21b oi the pole pieces, extending inwardly and toward. each other. The Lrshaped pole pieces, which: will hereinafter be. referred to as the auxiliary or hold-down pole pieces 20 and 2.1.,v are so constructed and. secured that the horizontal. arms 20!) and 21b thereof are. spacedv from the pole faces 81 and. 9 provided on; to leave, any air gap therebetween.

Pivoted in a suitable. manner to the underside oi thebase or frame, as by nonmagnetic pins.25, is an; elongated flatssurfaced armature 26 ot magnetizable. material. The armature. 26; is pivoted.- adjacentits rear edge, the armature extending; into the air gaps provided between the auxiliary pole, pieces 20 and. 21 and the. main pole pieces 6 and. 7f; the extending end of the armature being provided with the usual core. pins. 26:; to prevent. sticking.

With no energizing. current. flowing. through. the operating, windings 12 and. 13,. the. relay armature 26 will be held down against the hold-down pole pieces 2% and 21b by the polarizing, flux. of the small. permanent magnets 22. and 23 which. threads. through the pole piece 20, the armaturev 26,. the pole. piece- 21, the. core 3, backstrap 19 and through core. 2. The polarizing flux due: to the auxiliary magnets 16 and 17 does not influence the armatnre. 26 when no. energizing. current is flowing through the operating. windings ot the relay'dne to the closed. magnetic path provided for these magnets. The polarizing flux of the magnet 17 may be. traced from. its upper or north end through the upper extension 1111, down through the core 3, through the lower. extension 11:: to the lower or south end of the magnet, a small portion oi the flux branching off. to thread. downwardly through they soft. iron. shunt 15.. .A. similar path may be traced for the. polarizing time of auxiliary magnet 16, the flux passing. up through the associated core 2.

If. an energizing current. is applied. to. the operating windings 12 and 13- of. a polarity designated. on. the draw ings,, the operating flux. due to. the. energized. windings would pass downwardly through the core- 3: and upwardly through the. core 2, ..resp.ectiycly. The lower ends of the cores 3 and. 2. will be. ofi north. and south polarity, respectively. Due. to. the polarizing; flux of theauxiliary magnets 17 and. 16, the lower magnet-izableextensions 11a and 10a will also be of north and south. polarity, respectively. Thus the operating flux due to the energiz-ation of. the windings and the. polarizing flux due to the auxiliary windings combine at the pole pieces 7 and 6. to pick up the armature 26. The path of the combined fluxes may be traced from the pole. piece 7 across the air gap between the pole face 9 and; the. right-hand end of. the armature, through the, armature from right. to left, across the air gap between the. left-hand end of the annature to the pole face 8, through the main pole piece 6,. upwardly" through the core'2; through the backstrap 19, through the backstrap- 19 from left to right and then downwardlythrough the core 3'. The armature 26 is' thus picked up to open its back contacts and close its front contacts (notshown);

Should'the operating windings' of the relaybe connected the pole pieces 6 and 7,

core 2, respectively. The lower end of the core 3 will be a south pole While the lower end of the core 2' will he a north pole. As previously pointed out, the lower magnetizable extensions 11a and 10a due to the auxiliary magnets 17 and 16 will be of north and south polarity, respectively. The lower ends of the cores and their corresponding lower extensions being of opposite polarity will tend to confine the operating and polarizing fiuxes to the to; a. source of energizing current of opposite polarity, theopera-ting flux"di1e'-' tothe energized windings will thread upwardly through the core 3' and downwardly-through the local closed circuit comprising the core, the upper and lower extensions, and the auxiliary magnet so that no operating flux or auxiliary polarizing flux threads through the armature 26. Thus the opening flux due to the energization of the operating windings by a current of opposite polarity is ineffective in picking up the armature of the relay.

in the event a foreign particle is lodged between the lower face of the armature 26 and the hold-down pole pieces 20 and 21, the resulting air gap between the armature and; the. hold-downpole pieces would reduce the effectiveness of the polarizing flux of the hold-down magnets 22 and 23. In other relays of this type, the ineffectiveness of the. hold down magnets under such conditions. permitted the armature to. be picked up upon reverse energization of the operating windings. With the addition of the auxiliary magnets 16 and: 17, however, the polarizing flux of these magnets confines for the greater part, the reverse operating, flux to the closed magnetic path formed by the operating. Winding cores, the magnetizable extensions and the auxiliary magnets. The reverse polarizing flux, even though. many times. its usual magnitude, isthus ineffective to pick up the armature to close the front contacts of the relay. It has been found that, with reverse energizing. current through the operating windings and the armature held up by hand against the main pole pieces, upon release. of. the hold on the armature the reverse operating flux. was ineiiective to hold the armature against the main. pole pieces, the armature falling back against the auxiliary pole. pieces. This release of the armature due to the auxiliary polarizing. flu); despite the reverse energizing. current through the operating winding is extremely. advantageous in preventing false operation of they relay contactsin the event the relay is turned over prior to. its installation or possibly during an inspection period. The armature will not be held. against the pole faces 8 and. 9 as in previous relays. of this type, but will drop away when the relay is again righted.

A further advantage incorporated in the describe-d relay structure. is. the addition of the soft iron shunts 14' and. 15 for the auxiliary. magnets 16 and 1-7. These shunts act as keepers and provide amagnetic shunt path forprotecting the auxiliary magnets irom demagnetizattion. should: the operating windings of the relay be over energized as by a lightning surge. The screws 2A- securing, the. hold-down pole pieces 20 and 2.5.. and the holddown. magnets 22 and 23 to the main pole pieces 6 and 7 also serve as shunts to prevent demagnetization of the hold-down magnets, the screws forming a low eluctance path between the main pole pieces and the holddown pole pieces for the flux resulting from the overenergization of the operating. windin gs.

Although. I have herein shown and described only one. form of anelectrical relay embodying my invcntion, it is understood that various changes and modifications. may be made therein within the scope of the appended claims without departing. from the spirit and scope of my invention.

Having. thus describedmy invention, what I claim is:

1 An electrical relay comprising two spacedmagnetizableloops each. having a source of polarizing flux and a source of reversible operating flux, the polarizing fluxes in said loops being of opposite polarities; a magnetizable backstrap-interconnectingsaid. loops, a first pole piece for each. of said. loops; a. second pole; piece spaced. from each of said first pole pieces, each of said second. pole pieces being interconnectedto its respective first pole piece by a source of polarizing flux; and an armature pivotally mounted for movement in the air gaps between the first and second pole pieces, the polarizing fluxes of the pole piece sources holding said armature against the second pole pieces, the operating fluxes when of the same polarities as the polarizing fluxes at the first pole pieces moving said armature against said first pole pieces, the operating fluxes when of opposite polarities to the polarizing fluxes at the first pole pieces being ineffective to move said armature against said first pole pieces.

2. An electrical relay comprising two spaced magnetizable loops each having a source of polarizing flux and a source of reversible operating flux, the polarizing fluxes in said loops being of opposite polarities; a magnetizable backstrap interconnecting said loops, at first pole piece for each of said loops; a second pole piece spaced from each of said first pole pieces, each of said second pole pieces being interconnected to its respective first pole piece by a source of polarizing flux; and an armature pivotally mounted for movement in the air gaps between the first and second pole pieces, the polarizing fluxes of the pole piece sources holding said armature against the second pole pieces, the operating fluxes when of the same polarities as the polarizing fluxes at the first pole pieces moving said armature against said first pole pieces, the operating fluxes when of opposite polarities to the polarizing fluxes at the first pole pieces being ineffective to move said armature against said first pole pieces, a portion of the reverse operating flux of each loop aiding the polarizing fluxes of the pole piece sources.

3. An electrical relay comprising two spaced magnetizable cores interconnected at one end by a magnetizable backstrap and each provided at its other end with a pole piece, an operating winding on each core, means for supplying both of said windings with energizing current of one polarity or the other, an auxiliary pole piece for each core pole piece spaced therefrom and magnetically interconnected therewith by a source. of polarizing flux, a magnetizable armature pivotally mounted for movement in the air gaps between the core and auxiliary pole pieces, the polarity of the polarizing fluxes of the pole piece interconnecting sources being such to hold said armature against the auxiliary pole pieces, the operating fluxes due to the energization of said windings by a current of one polarity moving said armature against the core pole pieces; a source of polarizing flux for each of said cores, the polarizing flux at each core pole piece having the same polarity as the operating flux when the windings are energized by a current of the one polarity, the polarizing flux at each core pole piece having an opposite polarity to the operating flux when the windings are energized by a current of opposite polarity, the reverse operating flux being ineifective to move said armature against said core pole pieces.

4. An electrical relay comprising two spaced magnetizable cores interconnected at one end by a magnetizable backstrap and each provided at its other end with a pole piece, an operating winding on each core, means for supplying both of said windings with energizing current of one polarity or the other, an auxiliary pole piece for each core pole piece spaced therefrom and magnetically interconnected therewith by a source of polarizing flux, a magnetizable armature pivotally mounted for movement in the air gaps between the core and auxiliary pole pieces, the polarity of the polarizing fluxes of the pole piece interconnecting sources being such to hold said armature against the auxiliary pole pieces, the operating fluxes due to the energization of said windings by a current of one polarity moving said armature against the core pole pieces; a source of polarizing flux for each of said cores, the polarizing flux at each core pole piece having the same polarity as the operating flux when the windings are energized by a current of the one polarity, the polarizing flux at each core pole piece being of opposite polarity to the operating flux when the windings are energized by a current of opposite polarity, the reverse operating flux being ineffective to move said armature against said core pole pieces, a portion of the reverse operating flux aiding the polarizing fluxes of the pole piece sources.

5. An electrical relay comprising two spaced magnetizable cores interconnected at one end by a magnetizable backstrap and each provided at its other end with a pole piece, an operating winding on each core, means for supplying both of said windings with energizing current of one polarity or the other, an auxiliary pole piece for each core pole piece and spaced therefrom, a permanent magnet magnetically interconnecting each core pole piece and its associated auxiliary pole piece, a magnetizable armature pivotally mounted for movement in the air gaps between the core and auxiliary pole pieces, the polarity of the polarizing fluxes of the pole piece interconnecting magnets being such to hold said armature against the auxiliary pole pieces, the operating fluxes due to the energization of said windings by a current of one polarity moving said armature against the core pole pieces; a permanent magnet magnetically associated with each core, the polarizing flux at each core pole piece having the same polarity as the operating flux when the windings are energized by a current of the one polarity, the polarizing flux at each core pole piece having an opposite polarity to the operating flux when the windings are energized by a current of opposite polarity, the reverse operating flux being ineflective to move said armature against said core pole pieces.

6. An electrical relay comprising two closed magnetizable loops interconnected by a magnetizable backstrap; each of said loops including a core, two spaced parallel extensions interconnected at one end by the core and at the other end by a source of polarizing flux, an operating winding on said core, and a pole piece at one end of said core; an auxiliary pole piece spaced from each core pole piece, a source of polarizing flux for each auxiliary pole piece interconnecting the auxiliary pole piece and its associated core pole piece, a magnetizable armature pivotally mounted to be moved in the air gaps between the core and auxiliary pole pieces, and means for supplying an energizing current of one polarity or the other to both operating windings; the polarities of the polarizing fluxes of the pole piece sources being such to hold the armature against the auxiliary pole pieces when no energizing current flows through the operating windings, the operating flux due to energizing current of one polarity through the windings and having the same polarity as the polarizing fluxes at said core pole pieces moving said armature against the core pole pieces, the operating flux due to energizing current of the other polarity having a polarity opposite to that of the polarizing fluxes at the core pole pieces being ineffective to move said armature against the core pole pieces.

7. An electrical relay comprising two closed magnetizable loops interconnected by a magnetizable backstrap; each of said loops including a core, two spaced parallel extensions interconnected at one end by the core and at the other end by a source of polarizing flux, an operating winding on said core, and a pole piece at one end of said core; an auxiliary pole piece spaced from each core pole piece, a source of polarizing flux for each auxiliary pole piece interconnecting the auxiliary pole piece and its associated core pole piece, a magnetizable armature pivotally mounted to be moved in the air gaps between the core and auxiliary pole pieces, and means for supplying an energizing current of one polarity or the other to both operating windings; the polarities of the polarizing fluxes of the pole piece sources being such to hold the armature against the auxiliary pole pieces when no energizing current flows through the operating windings, the operating flux due to energizing current of one polarity through the windings and having the same polarity as the polarizing fluxes at said core pole 7' pieces movingsaid armature against the core pole pieces, the operating flux due to energizing current of the other polarity having a polarity'opposite to that of the polariz-- erating Winding on said core, and a pole piece at one end of said core; an auxiliary pole: piece spaced from each core pole piece, a: source of polarizing flux for each auxiliary pole piece magnetically interconnecting the auxiliary pole piece and its associated core pole piece, agravity biased magnetizablearrnature pivotally mounted to be moved in the air gaps between the core and auxiliary pole pieces, and means for supplying an cnergzing current of one polarity or the other to both operating windings; the polarities of the polarizing fluxes of the pole piece sources being such to hold the armature against the auxiliary pole pieces when no energizing current flows through the operating windings, the operating flux due to energizing current of one polarity through the windings and having the same polarity as the polarizing fluxes atsaid core pole pieces moving said armature against the core pole pi'eces,. the operating flux due to energizing current of the other polarity having a polarity opposite to that of, the polarizing fluxes at. the core poie pieces being. ineffective to move said armature against the core pole pieces.

9. An electrical relay comprising two closed magnetizable loops interconnected by a magnetizable baci strap; each of said loops including a core, two extensions interconnected atone end by the core and at the other end, by a source of polarizing flux, the polarizing flux in each loop being, of opposite polarity, an operating winding on said core, and, a pole piece at one end of said core; an auxiliary pole piece spaced from each core pole piece; a source of polarizing. flux for each auxiliary pole piece magnetically interconnecting the, auxiliary pole piece audits associated corepole piece,

a gravity biased magnetizablearrnature-pivotally mounted to be moved in the air gaps between the core and auxlia iary pole pieces, and means for supplying an energizing current of one polarity or the other to both operating windings; the polarities of the polarizing fluxes of the pole piece sources being such to. hold the. armature against the auxiliary pole pieces when no energizing current flows through the operating windings, the operatingflux due to energizing current oi one polarity through the windings and having the samev polarity as the polarizing fluxes at said core pole pieces moving said armature against the core pole pieces, the operating flux due to energizing current of the other polarity having a polarity opposite to that of the polarizing fluxes at the core pole pieces being ineffective to move said armature against the core pole pieces, aportionof' the reverse operating flux aidingthe polarizing fluxes of the'pole piece sources.

10; An electrical relay comprising two closed mag netizable loops interconnected by a magnetizahie backstrap; each of said loops including a core, two spaced parallel extensions interconnected at one end by the core and at the other end by a shunt and a permanent magnet, the polarizing flux otthe permanent magnet in each loop being of opposite polarity, an operating winding on said core between said extensions, and a pole piece at one end of said core; an auxiliary pole piece spaced from each core pole piece, a permanent magnet magnetically interconnecting each auxiliary pole piece and its associated core pole piece, a gravity biased niagnetizable armature pivotally mounted to be moved in the air gaps between the: core and auxiliary pole pieces, and means for supplying an energizing current of one polarity or the other to both operating windings; the polarities of the polarizing fluxes of the pole piece magnets being such to hold the armature against the auxiliary pole pieces when no energizing current flows through the operating windings, the

l operating fiux due to energizing current of one polarity through the windings and having the same polarity as the polarizing fluxes at said core pole pieces moving said armature against the core pole pieces, the operating flux due to energizing current of the other polarity having a polarity opposite to that of the polarizing fluxes at the core pole pieces being ineflective to move said armature against the core pole pieces.

11. An electrical relay comprising two closed magnetizable loops interconnected by a magnetizable backstrap; each of said loops including a core, two spaced parallel extensions interconnected at one end by the core and at the other end by a shunt and a permanent magnet, the polarizing flux of the permanent magnet in each loop being of opposite polarity, an operating winding on said core between said extensions, and a pole piece at one cndzof said core; an auxiliary pole piece spaced from each core pole piece, a permanent magnet magnetically interconnecting each auxiliary pole piece and its associated core pole piece, a gravity biased magnetizable armature pivotally mounted to be moved in the air gaps between the core and auxiliary pole pieces, and means for supplying an energizing current of one polarity or the other to both operating windings; the polarities of the polarizing fluxes of the pole piece mag-- nets being such to hold the armature against the auxiliary pole pieces when no energizing current flows through the operating windings, the operating flux due to energizing current of one'polarity through the windings and having the same polarity as the polarizing fluxes at said core pole pieces moving said armature against the core pole pieces, the operating flux due to energizing current of the other polarity having a polarity opposite to that of the polarizing fluxes at the core pole pieces being ineflective to move said armature against the core pole pieces, portion of the operating flux due to the reverse energizing current aiding the polarizingifluxes of the pole piece magnets threading the auxiliarypole pieces.

References Cited in the file of this patent Ashworth June it, 1940 

